Metallic, resilient annular seals that couple and seal first and second tubes have proved highly advantageous for use in the aircraft industry with tubes carrying high pressure and temperature fluid, especially in aircraft engines. Examples of these seals are disclosed in U.S. Pat. Nos. 4,054,306 to Sadoff, Jr. et al; and 4,071,268 and 4,071,269 to Halling et al.
While these resilient annular seals have proved capable of sealing at high temperatures, they are fragile because of their small thickness and are therefore prone to damage during manufacture, installation and misuse after installation. Such damage usually occurs when accidental radial forces compress or shear the annular seal past its elastic limit and causes plastic deformation of the material, which can render the seal useless.
Examples of other annular seals are disclosed in the following U.S. Pat. Nos: 2,381,426 to Allen et al; 2,774,618 to Alderson; 2,857,177 to Loetz; and 4,165,107 to Affa et al.
Thus, there exists a continuing need for improvement of metallic resilient annular seals for sealing and coupling tubes or pipes having high pressure and temperature fluid flowing therethrough.